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Becker, C. R.; Latussek, V.; Pfeuffer-Jeschke, A.; Łandwehr, G.; Molenkamp, L. W.

doi:10.1103/physrevb.62.10353

Cited by 91 publications

(65 citation statements)

References 41 publications

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“…6d we plot the temperaturedependence of the bandgap, E * E1 − E * H1 , which is experimentally measurable. 28 In the absence of phononinduced intersubband transitions, the gap increases linearly with temperature starting at low temperature. However, the inclusion of phonon-induced intersubband transitions and their thermal activation results in a kink in the temperature-dependence of the gap.…”

Section: Some Applicationsmentioning

confidence: 99%

“…The ensuing procedure is identical to that of Ref. [22], except that we take temperature-dependent bandgaps 28 for bulk HgTe and bulk Hg 0.32 Cd 0.68 Te. The solution at k ⊥ = 0 reveals discrete quantum well states, from which E1± and H1± have the lowest energies (here ± labels Kramers partners that are degenerate at k ⊥ = 0 due to time-reversal symmetry).…”

Section: Some Applicationsmentioning

confidence: 99%

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Phonon-induced topological insulation

Saha

Garate

2014

Phys. Rev. B

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We develop an approximate theory of phonon-induced topological insulation in Dirac materials. In the weak coupling regime, long wavelength phonons may favor topological phases in Dirac insulators with direct and narrow bandgaps. This phenomenon originates from electron-phonon matrix elements, which change qualitatively under a band inversion. A similar mechanism applies to weak Coulomb interactions and spin-independent disorder; however, the influence of these on band topology is largely independent of temperature. As applications of the theory, we evaluate the temperature-dependence of the critical thickness and the critical stoichiometric ratio for the topological transition in CdTe/HgTe quantum wells and in BiTl(S 1−δ Se δ )2, respectively.

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Section: Some Applicationsmentioning

confidence: 99%

Section: Some Applicationsmentioning

confidence: 99%

Phonon-induced topological insulation

Saha

Garate

2014

Phys. Rev. B

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“…By setting the energy of Γ 8 band at k = 0 in unstrained bulk HgTe to zero, Ω equals to the valence band edge E v (z) in the given layer. According to Latussek et al 29 and Becker et al, 30 Ω has a linear dependence on P and T :…”

mentioning

confidence: 99%

Pressure- and temperature-driven phase transitions in HgTe quantum wells

et al. 2016

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We present theoretical investigations of pressure and temperature driven phase transitions in HgTe quantum wells grown on CdTe buffer. Using the 8-band k·p Hamiltonian we calculate evolution of energy band structure at different quantum well width with hydrostatic pressure up to 20 kBar and temperature ranging up 300 K. In particular, we show that in addition to temperature, tuning of hydrostatic pressure allows to drive transitions between semimetal, band insulator and topological insulator phases. Our realistic band structure calculations reveal that the band inversion under hydrostatic pressure and temperature may be accompanied by non-local overlapping between conduction and valence bands. The pressure and temperature phase diagrams are presented.

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“…The Kane parameters of Hg 1−x Cd x Te can be assumed to be x-independent 10 , since the band structure dependence on the Cd composition x caused mainly by the variation of the band gap E g . And the band gap E g of Hg 1−x Cd x Te can be obtained in the previous work 12 .…”

mentioning

confidence: 99%

Electric field driven quantum phase transition between band insulator and topological insulator

Chang

2009

Applied Physics Letters

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We demonstrate theoretically that electric field can drive a quantum phase transition between band insulator to topological insulator in CdTe/HgCdTe/CdTe quantum wells. The numerical results suggest that the electric field could be used as a switch to turn on or off the topological insulator phase, and temperature can affect significantly the phase diagram for different gate voltage and compositions. Our theoretical results provide us an efficient way to manipulate the quantum phase of HgTe quantum wells. PACS numbers: 73.43.Nq, 72.25.Rb, 73.61.Ga, Topological insulator (TI) is a very recent discovery and has attracted a rapid growing interests due to its novel transport peoperty 1,2,3,4 . Topological insulators possess a gap in the bulk but a gapless edge states at its boundary, therefore display remarkable transport property due to the presence of the topological edge states, e.g., quantum spin Hall effect (QSHE). The QSHE is protected by the time-reversal symmetry and robust against the local perturbation, e.g., impurity scattering. Searching for new TI becomes a central issue in this rapid growing field. Recently, the HgTe QWs have been demonstrated to be a 2D TI to exhibit the QSHE 3 and BiSb alloys have been proven to be a 3D TI with a conducting surface 5 . A few other materials, such as InAs/GaSb QWs, BiSe, BiTe and SbTe alloys 6 , are also predicted to be TIs and demonstrated experimentally. Besides finding new TI materials, searching the ways to drive a band insulator (BI) into a topological insulator is also important. It has been demonstrated to be possibly realized by tuning the thickness of HgTe QW. However, tuning the thickness of QW is not a convenient way to drive the phase transition. Therefore other efficient ways such as external fields and temperature is highly desirable to drive a BI into a TI. These ways would be very important for both potential device applications and basic physics.In this Letter, we demonstrate theoretically that a BI can be driven into a TI by tuning external electric field in CdTe/Hg 1−x Cd x Te/CdTe QWs based on the self-consistent calculation of the eight-band Kane model and the Poisson equation. We demonstrate electric field can change the interband coupling significantly and consequently leads to strong variations of the band structures, i.e., therefore leads to the quantum phase transition from a BI to a TI. We also show phase diagrams at plenty of parameters and consider the temperature effect on the phase transition. One can see that the critical gate voltage of external phase transition can be reduced at high temperature, small Cd composition and thick thickness of well. Our results could be useful in finding the optimized parameters to realize the phase transition in experiment.We consider a CdTe/Hg 1−x Cd x Te/CdTe QW grown along the [001] direction [see Fig. 1 (a) inside the QW will redistribute due to the effect of the electric field. The charge redistribution induces an internal electric field, which affects the charge density distribution, therefore we n...

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Band structure and its temperature dependence for type-IIIHgTe/Hg1−x

Cited by 91 publications

References 41 publications

Phonon-induced topological insulation

Phonon-induced topological insulation

Pressure- and temperature-driven phase transitions in HgTe quantum wells

Electric field driven quantum phase transition between band insulator and topological insulator

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